...... to help get the steam to the farthest parts of the building quicker (similar to what Gerry Gill and Steve Pajek describe doing with added main vents on conventional systems in Dan Holohan's book "The Lost Art of Steam Heating Revisited"). I found this website and Dan’s books just a few months ago, and have learned more about steam systems in those months than I had in the 16+ years prior. It currently takes more than 4 minutes from the time the takeoff gets hot, for the steam to make it to the ends of both mains. I know if I can shorten that transit time, I can heat the building just as well with shorter burns; and the Heat-timer will shorten the burns automatically, because the system-sensor will be satisfied sooner.
I'm soliciting advice, suggestions and comments on this idea. This would be done as part of my off season projects, which already include replacing crazy-oversized F&T traps, and installing orifices in the radiator inlets.
A bit of background:
This is in an eight story, 72 unit apartment building in Northwest DC built in the early 40's. It has 2 steam mains of un-equal length, that run in opposite directions around the perimeter of the building in the sub-basement and basement levels (the sub-basement is only partial) feeding 282 cast iron radiators. With the exception of those in the bathrooms, all radiators are located against exterior walls, underneath windows. Both mains end several feet apart, under the 08 tier of apartments; the 08 tier living rooms each have two radiators, one fed off of each main. None of the risers are dripped.
It was originally a Dunham Vari-Vac system, which was converted to an ordinary vacuum return system, with a Shipco LRV (condensate/vacuum pump and receiver) and a Heat-Timer EPU (with a very poorly placed system sensor) in the late 80’s. In the early 90’s, the giant round steel boiler was replaced with a Weil-McLain 1288 series 1.
I took over managing the building in 2003, and have been learning about steam as I go. Rebuilt all the radiator traps (Dunham Bush, and Mepco 1E’s) the first time in ’05. In ’08 I replaced the Heat-Timer EPU with a Heat-Timer SRC Platinum, and relocated the system sensor to the top of the last supply riser with a crossover trap (to prevent the tenant in 808 from ruining me by closing the radiator valve). Installed Danfoss TRV’s on all the larger radiators in ’18 and on as many of the smaller (kitchen and bath) radiators as we could last year (had to skip some that are in such tight places that there simply isn’t room for the valve). I’ve been using temperature loggers since before I changed the Heat-Timer, to monitor air temperature, and on pipes and radiators to help with balancing and timing. This season the temperature difference between the warmest and coolest units is about 3 degrees, down from 10+ degrees when I started keeping track.